Abstract

Of the three alcohols studied, n-butanol was the most effective. At 0.15 M it prevented stomatal opening whereas methanol has the same effect at 0.5 M and ethanol at 0.9 M. Cytoplasmic movement is not affected by n-butanol but the stomatal plastids are sometimes altered. It is supposed on the basis of numerous reports in the literature, that the lipophilic nature of this alcohol must have a major effect on the lipid constituents of the cell membranes and thus render impossible the maintenance of the low osmotic potential required for stomatal opening. This conclusion is supported by the fact that the stomata did not reopen in CO2 free air. Another possible effect is a disturbance of the redox equilibrium of the cells, particularly the NADH2:NAD ratio, with the result that the active pumping system cannot perform the work required to drive in the cations. The lipid components of ATPase can also be damaged. It is concluded that when alcohols are used as solvents, care must be taken to avoid causing subtle membrane lesions.

Footnotes

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